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nds32/ftrace: Support static function tracer

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This patch support the static function tracer. On nds32 ABI, we need to
always push return address to stack for __builtin_return_address can
work correctly, otherwise, it will get the wrong value of $lp at leaf
function.

Signed-off-by: Zong Li <zong@andestech.com>
Acked-by: Greentime Hu <greentime@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>
This commit is contained in:
Zong Li 2018-08-15 10:45:59 +08:00 committed by Greentime Hu
parent 487913ab18
commit a18082575c
5 changed files with 59 additions and 0 deletions
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1
arch/nds32/Kconfig
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@ -40,6 +40,7 @@ config NDS32
select NO_IOPORT_MAP select NO_IOPORT_MAP
select RTC_LIB select RTC_LIB
select THREAD_INFO_IN_TASK select THREAD_INFO_IN_TASK
select HAVE_FUNCTION_TRACER
help help
Andes(nds32) Linux support. Andes(nds32) Linux support.

4
arch/nds32/Makefile
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@ -5,6 +5,10 @@ KBUILD_DEFCONFIG := defconfig
comma = , comma = ,
ifdef CONFIG_FUNCTION_TRACER
arch-y += -malways-save-lp -mno-relax
endif
KBUILD_CFLAGS += $(call cc-option, -mno-sched-prolog-epilog) KBUILD_CFLAGS += $(call cc-option, -mno-sched-prolog-epilog)
KBUILD_CFLAGS += -mcmodel=large KBUILD_CFLAGS += -mcmodel=large

20
arch/nds32/include/asm/ftrace.h Normal file
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@ -0,0 +1,20 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __ASM_NDS32_FTRACE_H
#define __ASM_NDS32_FTRACE_H
#ifdef CONFIG_FUNCTION_TRACER
#define HAVE_FUNCTION_GRAPH_FP_TEST
#define MCOUNT_ADDR ((unsigned long)(_mcount))
/* mcount call is composed of three instructions:
* sethi + ori + jral
*/
#define MCOUNT_INSN_SIZE 12
extern void _mcount(unsigned long parent_ip);
#endif /* CONFIG_FUNCTION_TRACER */
#endif /* __ASM_NDS32_FTRACE_H */

6
arch/nds32/kernel/Makefile
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@ -21,3 +21,9 @@ extra-y := head.o vmlinux.lds
obj-y += vdso/ obj-y += vdso/
obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o
ifdef CONFIG_FUNCTION_TRACER
CFLAGS_REMOVE_ftrace.o = $(CC_FLAGS_FTRACE)
endif

28
arch/nds32/kernel/ftrace.c Normal file
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@ -0,0 +1,28 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/ftrace.h>
#include <linux/uaccess.h>
#include <asm/cacheflush.h>
extern void (*ftrace_trace_function)(unsigned long, unsigned long,
struct ftrace_ops*, struct pt_regs*);
noinline void __naked ftrace_stub(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *regs)
{
__asm__ (""); /* avoid to optimize as pure function */
}
noinline void _mcount(unsigned long parent_ip)
{
/* save all state by the compiler prologue */
unsigned long ip = (unsigned long)__builtin_return_address(0);
if (ftrace_trace_function != ftrace_stub)
ftrace_trace_function(ip - MCOUNT_INSN_SIZE, parent_ip,
NULL, NULL);
/* restore all state by the compiler epilogue */
}
EXPORT_SYMBOL(_mcount);